Khatri, H 
ORCID: 0000-0001-6559-9059 and Williams, RG ORCID: 0000-0002-3180-7558
(2025)
Contrasting Fast and Slow Ocean Thermal, Carbon and Nutrient Responses to the North Atlantic Oscillation
Global Biogeochemical Cycles, 39 (12).
ISSN 0886-6236, 1944-9224
Abstract
Thermal and biogeochemical states of the North Atlantic Ocean are affected on seasonal to decadal timescales by atmospheric forcing associated with the North Atlantic Oscillation (NAO). An NAO–based composite approach is applied to an Earth system model to reveal the fast and slow responses of the ocean to atmospheric impulse forcing. Over the seasonal boundary layer, the atmosphere induces a “fast”, seasonal ocean response driven by anomalies in the air–sea flux, vertical entrainment and Ekman transport. This fast response to an NAO (Formula presented.) anomaly results in negative temperature and positive carbon and nutrient anomalies over the subpolar gyre, and positive temperature and negative carbon and nutrient anomalies over the subtropical gyre. The “slow” response on inter-annual timescales involves changes in meridional overturning, tracer transport and entrainment. The slow response leads to a redistribution of anomalies between subpolar and subtropical regions, generating opposing–signed tracer anomalies in the subpolar and subtropical North Atlantic Oceans. These ocean responses also involve changes in the mixed-layer depth, as well as the associated changes in entrainment and turbulent mixing rates, which are particularly important for the carbon and nutrient responses given their large vertical gradients. Modifications in nutrient concentrations subsequently influence biological activity and biomass production. These thermal, carbon and nutrient responses to atmospheric events linked to the NAO can persist for up to a decade, often characterized by opposing–signed temperature and carbon anomalies, along with contrasting changes in the subtropical and subpolar gyres.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | North Atlantic Oscillation, Ocean carbon and nutrient variability, North Atlantic decadal variability |
| Divisions: | Faculty of Science & Engineering Faculty of Science & Engineering > School of Environmental Sciences Faculty of Science & Engineering > School of Environmental Sciences > Earth, Ocean and Ecological Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 08 Dec 2025 09:56 |
| Last Modified: | 28 Feb 2026 11:51 |
| DOI: | 10.1029/2025GB008519 |
| Open Access URL: | https://agupubs.onlinelibrary.wiley.com/doi/10.102... |
| Related Websites: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3195899 |
| Disclaimer: | The University of Liverpool is not responsible for content contained on other websites from links within repository metadata. Please contact us if you notice anything that appears incorrect or inappropriate. |
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